FOUR years after making his debut with the New York-set horror flick “Countdown” — in which three Thai teens get more than they bargained for from a goateed drug dealer called Jesus — 36-year-old helmer Nattawut Poonpiriya manages to ace a far-from-standard test, turning high school exams into an intense thrilling ride.

Based on recent revelations about real-life scandals in the international college-admission Scholastic Assessment Tests (SAT), “Bad Genius” scores high marks as a ceaselessly entertaining thriller that cedes little ground to the cheap comedy and sentimentality of recent Thai hits. Nattawut admitted he watched “The Conversation” and “All the Presidents’ Men” for inspiration, and it shows as the film flourishes through its simple narrative and taut editing.

With exams now basically an essential part of modern life, “Bad Genius” could easily resonate across various demographics — and even qualify as a mildly-worded social critique, with its allusions to the inequality and corruption engulfing the young Thai protagonists. And just like his characters, Nattawut has turned his exam scams into big business: The May 3 release topped the Thai box office during its opening weekend and now stands as the highest-grossing homegrown title in Thailand this year, with takings of nearly US$3.3 million. The film opens the New York Asian Film Festival on June 30, and it wouldn’t be a surprise if someone snaps up remake rights after that.

The titular heroine (or anti-heroine) here is straight-A student Lynn (played by model Chutimon Chuengcharoensukying in her first screen role), who, as the film begins, has just enrolled in an elite school. Hailing from a lower middle-class background — her father (1980s pop singer-producer Thaneth Warakulnukroh) is a plain, recently divorced schoolteacher — the teenager discovers, much to her chagrin, that fraud is endemic in her new surroundings. While the school charges students “tea money,” teachers leak exam papers to students in return for “tutoring fees.”

Watching her father scavenge money for her tuition, the good girl soon turns bad as she develops a plan to earn a quick buck. Egged on by the beautiful but dim-witted Grace (Eisaya Hosuwan) and her rich but equally dense boyfriend Pat (Teeradon Supapunpinyo), Lynn devises a system by which she can relay answers to them — and anyone who’s willing to pay — during tests. Beginning with a small-scale experiment in a classroom, Lynn’s operation eventually balloons into a derring-do venture with a bigger test taking place in the school hall as she scrambles to beat a cheat-proof device in the exam papers.

Having somehow passed the test on that one — a mission Nattawut conveys very impressively via a mise-en-scène resembling that of a heist more than a high-school comedy — Lynn’s fortune-making enterprise grinds to a halt because of a complaint lodged by her impoverished, equally talented but much more scrupulous rival, Bank (Chanon Santinatornkul). Soon enough, however, Lynn finds bigger fish to fry. Asked by Grace and Pat for her help in their efforts to score decent results at the STIC tests — a fictional equivalent of the SAT — she comes up with a more elaborate and profitable venture, one that would require more logistics, a trip to Australia and, most problematically, Bank’s help.

Devoid of the fantastical gadgets that many a 21st century media-savvy maverick would conveniently throw in, “Bad Genius” is as markedly low-tech as its unassuming title: Here, the scammers operate with consumer-grade smartphones, pencils and old-school printing presses, table-tapping fingers, strategically timed bathroom breaks and extreme ways of feigning sickness. Nattawut has managed to make all this work (glossing over a few problems in the plot) with his dynamic storytelling and thanks to Phaklao Jiraungkoonkun’s camerawork and Chonlasit Upanigikit’s cutting.

While allowing just enough of a glimpse of the internal anguish of Lynn and Bank, the director — here helped by engaging turns from Chutimon and Chamon — refrains from expanding that emotion into cliched melodrama. In an audacious move, he denies Bank a chance at redemption, as the boy emerges from his ordeal with his values utterly and dismayingly transformed.

Perhaps to avoid being accused of advocating that crime pays, Nattawut has Lynn repent on her misdeeds. But he keeps that note brief and devoid of moralizing or high drama. “Bad Genius” ultimately is more about escapades than its consequences, showing that bad things continue to happen in this crooked world.